Question

I have a very simple table called Member, which consists of the following:

CREATE TABLE [dbo].[Member](
    [Member_MemberId] [int] IDENTITY(1000,1) NOT NULL,
    [Member_ExternalId] [varchar](32) NULL,
    [Member_ConsumerId] [varchar](32) NULL,
 CONSTRAINT [PK_Member] PRIMARY KEY NONCLUSTERED 
(
    [Member_MemberId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

I’m running a query using EF 4.0 from a datacontext as follows:

return Members.SingleOrDefault(member => member.ExternalId == externalId);

The generated SQL looks like this:

exec sp_executesql N'SELECT TOP (2) 
[Extent1].[Member_MemberId] AS [Member_MemberId], 
[Extent1].[Member_ExternalId] AS [Member_ExternalId], 
[Extent1].[Member_ConsumerId] AS [Member_ConsumerId]
FROM [dbo].[Member] AS [Extent1]
WHERE [Extent1].[Member_ExternalId] = @p__linq__0',N'@p__linq__0 varchar(8000)',@p__linq__0='Paul'

From a performance POV, this query is suboptimal, given that it automatically casts the Member_ExternalId column as varchar(8000), when the column itself is limited to varchar(32).
Is there a way to force EF to generate on-the-fly parameters of size equivalent to their corresponding rows?

Answer 1

There doesn’t seem to be a way of implementing this directly. I assume that it’s a built-in feature to guarantee consistency across execution plans. I’ve replaced the query with a stored procedure in the meantime.